Starter drive



Feb. 15, 1944. w, Q ROSE 2,341-516 STARTER DRIVE Filed June 21, 1941 INVENTOR. M4 afl/W'O. 160.545

-E/, L? f li L5 25 Q7 7927 M Z) ATTORNEY Patented Feb. 15, 1944 UNITED STATES PATENT OFFICE STARTER DRIVE William 0. .Rose, Wyandotte, Mich.

Application June 21, 1941, Serial No. 399,043 (01. 74-7) 3 Claims.

The present invention pertains to a novel starter drive for automobile engines or the like; particularly the electrically operated mechanical starter for the internal combustion engine of a motor vehicle. The device is also useful in connection with stationary and other engines that must be turned over in starting.

The starter drive is of the'type including a power driven sleeve or screw on which is rotatably threaded a gear which advances, when the screw is driven, into engagement with the gear teeth on the flywheel of the motor to be started.

Ordinarily the starter switch associated with the engine closes the starter motor circuit, whereupon the worm shaft is rotated and the gear thrown into mesh with the flywheel gear. This operation causes the well known clashing of gear teeth, since the worm shaft is driven with sufficient force to turn the engine over.

One of the objects of the present invention is to reduce or eliminate such clashing. This is accomplished by turning the worm shaft at two different speeds, first a low speed for merely bringing the starter gear into mesh with the flywheel gear, and second a high speed for turning over the motor. The first or low speed is too low to cause serious clashing. The two speeds are effected by suitable electrical devices described in detail below.

In the usual starter drive operation, as in the present case, the starter gear is thrown out of mesh with the flywheel gear by the overdrive of the motor after the latter has started firing. The momentum of the moving parts, such as the starter gear and the worm shaft, is merely absorbed by friction with other parts. Such action introduces shock and wear in the apparatus, and another object of the present invention is to provide other means for absorbing the residual motion or momentum. This means consists of impeding devices on the Worm shaft and starter gear. The resistance which they p esent to the active operation of the device is insignificant, but they are quite effective in taking up the residual motion after the starter gear has been thrown out of mesh with the flywheel gear.

The invention is fully disclosed by way of example in the following description and in the accompanying drawing in which:

Figure 1 is a side elevation, partly in section, of the device in active position;

, Figure 2 is an elevation of the device in idle position;

Figure 3 is a section on the line 33 of Figure 1;

Figure 4 is a section on the line l4 of Figlire 1;

Figure 5 is a detail elevation fa modification;

Figure 6 is a section on the lined-5 of Figure 1, and

Figure '7 is a wiring diagram.

Reference to these views will now be made by use of like characters which are employed to designate corresponding parts throughout.

The starter drive shaft or worm shaft 1 is usually a prolongation of the shaft of the electric starting motor, and is fitted with an exter nally threaded sleeve 2. At one end a Woodrufi key 3 secures the sleeve to theshaft. A nut 4 is threaded on the free end of the sleeve and retains the key. Together the shaft 6 and sleeve 2 constitute a worm shaft.

The starter gear 5 is threaded on the sleeve 2 in the usual manner'but is modified, according to the invention, by an integral sleeve 6 extending therefrom towards the starter housing I or away from the nut 4.

The free end of the sleeve 6 is formed with a channel 8 for receiving a brake ring 9, A brake guide in the form of a fork l0 extends from the housing I and slidably receives a finger H extending from the brake 9 to hold the ring against rotation.

The ring 9 is formed with several apertures l2, and in each aperture is a pair of friction discs I3 with an interposed spring I4 holding the discs against the sides of the channel 8.

The channelled end of the sleeve 6 is formed with an enlarged bore l5, and the corresponding end of the sleeve 2 receives a nut i6 extending into the recess l5. The nut is formed with a collar ll lying beyond the sleeve 6 and channel 8 as illustrated. The collar, which serves as a brake drum, is engaged by a pair of brake shoes If! each having one end pivotally mounted on the housing 1 as indicated by the numeral l9, and the remaining ends joined by a spring 20 which draws the shoes against the drum or 001- In the wiring diagram, the battery 2| is connected to the starting motor 22 by a conductor 23 to form a primary circuit. In this circuit is comprised an electro magnetic switch 24 actuated in any suitable manner but preferably by the ignition key 24. The circuit also contains a bimetal switch 25 and the usual vacuum operated switch 26. The bi-metal switch is constructed to pass a current of 30 to 40 amperes to turn the motor 22 slowly and bring the gear 5 slowly into mesh with the flywheel gear 21. In

this movement the discs l3 hold the gear 5 against turning with the slowly rotating worm 2, so that the gear is moved lengthwise of the worm as desired. The nut "5 serves as a stop for the gear 5 when it reaches its proper position in mesh with the flywheel gear 21.

Another conductor 28 between the battery l and the motor 22 forms a secondary circuit and contains the starter switch 29 which passes the full battery current to the motor. I This circuit provides sufiicient power for driving the 'flywheel gear and starting the engine.

When the engine fires, the vacuum created thereby opens the vacuum switch 26 and the primary circuit. It will be understood, however, that this is not the ignition circuit but is merely operated from the ignition key. The ignition circuit is conventional and need not 'be illus-- trated.

With the firing of the motor, the overdrive throws the starter gear 5 into the idle position out of mesh with the flywheel gear 21. The idle rotation of the gear 5 is absorbed for the most part by the disc I 3, while the momentum of the shaft I and sleeve 2 is taken up by the brake shoes I 8, thereby eliminating undue shock and wear on the parts.

-An alternative method of securing the worm sleeve 2' on the main shaft I is illustrated in Figures 5. and 6. The sleeve has a lengthwise slot 30 cut through its end, and in this slot is fitted a key 3| entering a notch 32 in the shaft. In order to prevent the key from falling out, a reinforcing collar 33 is slipped over the sleeve and key. The collar is retained by a stud 34 screwed therein and also passing through the sleeve 2' into the shaft l', whereby the driving ,ring against rotation,

connection is also reenforced and the key 3| prevented from shearing.

Although specific embodiments of the invention have been illustrated and described, it will be understood that various alterations in the details of construction may be made without departing from the scope of the invention as indicated by the appended claims.

What I claim is:

1 In a starter drive ofthe class described, a worm shaft, a starter gear threaded on said shaft and adapted to rotate thereon, said gear being formed with a channel, a brake ring rotatably mounted in said channel, means holding said and friction members mounted in said ring and yieldably held against the sides of said channel.

2. In a starter drive of the class described, a worm shaft, a starter gear threaded on said shaft and adapted to rotate thereon, said gear being formed with a channel, a brake ring rotatably mounted in said. channel, means holding said ring against rotation, and friction members mounted in said ring and yieldable braking means acting on said shaft. 7

3. In a starter drive of the class described, a worm shaft, a starter gear threaded on said shaft and adapted to rotate thereon, means for r0- tating said shaft, said gear being formed with a channel, a brake ring rotatably mounted in said channel and formed with apertures from side to side, means holding said ring against rotation, a pair of friction disks mounted in each of said apertures, and a spring between each pair of disks and holding them yieldingly against the sides of said channel.

WILLIAM O. ROSE. 

